Types Of Estimates In Quantity Surveying

This construction article sheds light on fundamental types of estimates found in quantity surveying. Types of Estimates are segregated on the basis of how project is measured. Besides, the level of accuracy determines which estimate is perfect for a specific project.

Given below the types of estimates which are mostly recognized in construction projects. a) Detailed Estimate b) Assembly Estimate c) Unit Estimate

Detailed Estimate: Detailed Estimate finds out the quantity and cost of all the materials associated with a construction project.

Detailed estimating is also known as “Prime Cost”, “Bottoms Up” or “Grass Roots” estimates. To carry out these types of estimates, an in-depth and comprehensive analysis of all the tasks is necessary for rendering a project or product.

These types of estimates are expensive to generate as lots of time and effort are required to carry out the estimate. But the perfectness is very good.

These types of estimate are performed when there are all the information like drawings, process sheets, planning etc. Each item is recorded on estimate work-up sheet. Project is divided into deliverable. Each deliverable contains assigned time and cost.

After the formation of WBS (work breakdown structure), make sure that each deliverable is arranged in perfect time to execute the project in scheduled time.

Detailed estimate contains the following costs:

1. Labor 2. Material 3. Equipment 4. Insurance 5. Bonds 6. Overheads etc.

Assembly Estimate: For an Assembly Estimate, instead of bidding for every separate components of the project, The Estimator bids the components in groups which are called as assemblies.

Assembly method applies sequential approach that describes how building will be built in. In order to instantly find out cost variance of two assemblies, two assemblies are replaced in place of each other.

Ref: civilengineeringdaily.com

An Assembly estimate is suitable if it is applied as a budgeting tool in the planning phases of a project as the correctness of the estimate is generally 15% +-.

Standard estimate of substructure and foundation estimate is given below :-

Unit Estimate: Unit estimates are performed by multiplying unit area of the building by cost per unit area and then modifying the price to pay off for variances in building height, length of the building perimeter, and other building components.

Unit estimates are also known as square-foot estimates as square foot is applied for maximum common area unit. These types of estimates belong to “educated guesses” due to less precision level.

There are two portions in Unit estimate: price per unit of work associated with various stages of project and Calculation of actual work that is accomplished on site.